Dry eye is a disorder of the eye due to tear deficiency or excessive evaporation, which causes damage to the ocular surface and is associated with symptoms of ocular discomfort such as itchiness, irritation, foreign body sensation, redness, photophobia, pain and paradoxical tearing from corneal irritation. These symptoms are often worse toward the end of the day or after prolonged periods of time requiring vision attention such as reading, driving, or computer work. Tens of millions of people suffer from these debilitating symptoms.
The causes of dry eye disorders have been attributed to either decreased tear production (aqueous-deficient dry eye) for example, lacrimal gland disease, and/or excessive tear evaporation (evaporative dry eye) for example, arising from contact lens wear. Meibomian gland dysfunction (MGD) is considered to be a sign of dry eye disorders. Phenotypic changes within, or alteration of the dynamic composition of the ocular commensal bacteria such as coagulase-negative staphylococci, Staphylococcus aureus and Propionibacterium acnes may create an imbalance and may trigger release of bacterial virulence factors such as endotoxins, lipopolysaccharides, and/or lipase causing eyelid inflammation, degradation of lipids secreted by meibomian glands, and directly influencing tear film stability and favouring tear evaporation. The greatest bacterial lipolytic activity was found in the patients with MGD. Commonly used dry eye treatments increase humidity of the ocular surface and improve symptoms by use of lubricants/artificial tears and/or topically applied anti-inflammatory medication such as cyclosporine A or corticosteroids. Oral antibiotics such as tetracycline and its derivatives have also been used in management of some types of MGD. However, these available treatments do not represent a cure and excessive antibiotic use is known to be problematic given the tendency for subjects to develop antibiotic resistance. Thus, there is a need to develop novel and better dry eye therapies.
US 2010/0016264 describes compositions and methods for treating eye conditions, specifically dry eye, with progestagen with or without testosterone. For example, a composition is described which includes 15% progesterone in Vanicream®. U.S. Pat. No. 4,485,029 describes the use of glycerol monolaurate in combination with one or more other anti-microbial agents for cleaning, disinfecting or preserving contact lenses. The glycerol monolaurate is used at concentrations which seem to exhibit anti-microbial, or at least bacteriostatic, properties and were not applied directly to the eye. U.S. Pat. No. 5,472,703 describes an ophthalmic lens that claims to lessen the risk of bacterial infection in the cornea. The lens has impregnated in it, or coated on the surface, an ester of polyhydric aliphatic alcohol and a fatty acid.
Dry eye disorders and ocular discomfort associated with dry eye disorders are still a substantial problem. The present invention is directed to overcoming and/or ameliorating at least one of the disadvantages of the prior art as will become apparent from the discussion herein.
Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia or any other jurisdiction or that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art.